A layer of AlTiN coating was deposited on YT14 cutting tool by CAIP (cathodic arc ion plating), the COFs (coefficients of frictions) of the AlTiN coating under different loads at high temperature of 800C were investigated with a high temperature wear tester. The worn morphologies, chemical elements and phases of the coating after wear were analyzed with a SEM (scanning electron microscopy), EDS (energy dispersive spectrometer) and XRD (X-ray diffraction), respectively, the contours of worn traces were investigated with a comprehensive measurement tester for material surface performances. The effects of loads on COFs and wear resistance of the AlTiN coating were analyzed, and the wear mechanism of the AlTiN coating at high temperature was also discussed. The results show that the mixed oxides of Al2O3 and TiO2 are produced under high temperature to improve the lubrication performance and wear resistance of the AlTiN coating. The average COF of the coating under the load of 5N, 7N, and 9N is 0.6495, 0.5897, and 0.3898, respectively. The COFs of the coating decrease with the loads increasing, as a result, the AlTiN coating is suitable for heavy loads at high temperature. The friction and wear mechanisms of the AlTiN coating are primarily composed of oxidation wear and abrasive wear, accompanied by fatigue wear and adhesive wear.